pogotango

when i start my car with keyless go, it says a malfunction of "key, check battery"

do i have to take my car to the dealer...

when i start my car with the key in the hole, its fine.

amdeutsch

Buy new batteries. How to replace them is listed on the forum as well as in your manual.

hecdog

yeah , you can find new batteries at radio shack or target, etc. They're pretty common batteries. Do a quick search for "Remote Batteries" on the forum for more information.

pogotango

brabusw209amg

my batteries last me about 3 months only. It sucks. Before there's a warning, I can't even open my doors.

Barry45RPM

My Keyless Go batteries last well over a year.

Roar

I had the same warning on the e55 Wagon I just bought. Was told that the keyless go batteries wear out a lot faster than on non-kg remotes. A salesguy put in the new batteries, but it didn't seem to "synch" with the car when I used it for the first time. All ok now after taking it back.

pinebaron

Having replaced mine two weeks from new (with GE/SANYO), I have been on the same set for the last 5 months. I keep a spare set, just in case.